1. Field of the Invention
The present invention relates to the field of folding multi-section bridges and is primarily concerned with the hingeing of the sections.
2. Discussion of Prior Art
It is well known to deploy transportable bridges directly from launch vehicles to enable rapid crossing of obstructions for example rivers and ditches by vehicles such as tanks.
Bridges suitable for this purpose are commonly constructed from two sections that are hinged together in end to end relation. Each section usually comprising a pair of spaced parallel trackways which constitute the upper surfaces of box section girders which are open on-their lower faces. The trackways are spaced by transverse beams welded to the sides of the box section girders which face one another. The spacing between the trackways being chosen to accommodate the track or wheel spacing of the vehicles for which the bridge is designed.
The two bridge sections are joined by hinges each of which extends across the width of a trackway, and permit the bridge to fold from a deployed configuration in which the trackways of two sections are aligned to a folded configuration in which one section lies on top of the other, and the trackways are outermost.
One major disadvantage of the bridges currently in use is that the height occupied by a folded bridge is at least the sum of the section depths. When a bridge is to be transported on a vehicle in the folded configuration, the combined height, length and width of the vehicle and the bridge are subject to limitations such as road bridge height, curvature of minor roads and carriage way width respectively.